There's a new bike in the garage.
You bought it last week after taking a long, critical look at yourself in the mirror post-shower and deciding you really had to do something about that body. So now, every time you go into the garage the new bike's there, gleaming.
It seems to be screaming: "Come on, take me for a ride!" If it was a puppy, it would be running around and around your legs, a leash in its mouth.
So, nothing for it but to go for that first ride.
If it's the first time you have ridden a bike, and you bought a mountain bike, start by riding on a park, so you will enjoy a soft landing if things go awry.
Check there's enough air in the tyres, then off you go.
Play around with the gears and work out which ones are good for slow riding and which ones make the bike fair whizz along.
You will soon learn that when you're on the smallest gear on the front derailleur and the largest cog on the back, that's the slowest gear, which cyclists know affectionately as granny gear.
On a 27-speed mountain bike, in granny gear you can creep uphill at just 4kmh - slower than walking pace.
Conversely, the largest cog on the front and the smallest on the rear is the top-speed gear.
Also practise using the brakes.
The right lever controls the front brake and the left lever the rear. The most common new-cyclist mishap is to jam on the front brake while turning sharply, producing what cyclists call a face-plant as you fly over the handlebars. You need to favour the back brake in tricky situations like this.
If you feel you will have no problems riding your new bike but need to become familiar with the gears, go somewhere away from traffic where you can tootle along and look down at the gears without having to worry about dodging trucks.
Dunedin has two brilliant new places for this.
The first is the West Harbour cycleway.
At present, this wide, smooth-seal track stretches 2.5km from the boat marina in Magnet St to Maia.
Eventually it will go all the way to Port Chalmers.
The second top place to learn is the section of John Wilson Ocean Drive which is off-limit to all vehicles apart from bikes and prams.
Once you have become familiar with the gears and brakes and the position your saddle should be in for efficient pedalling (have one pedal at its lowest position, foot on the pedal, and ensure your knee is only just bent), you are ready for some more adventurous biking.
If you bought a mountain bike, head for some quiet gravel roads in your district and also search out other cycle paths and bike tracks in your area - bike shops are a good starting point.
You will be surprised how many tracks there are and what fun you can have linking them up.
Often when heading over to the harbour cycleway I zip along the Dunedin Railway Station platform to keep away from traffic.
When riding on public roads, observe all the road rules and keep in the back of your mind the fact that if a tonne of steel collides with a small collection of lightweight tubes, there is only going to be one outcome and it won't be good for the cyclist.
When you first jump on your new bike, you don't have to be supremely fit to start your training.
If you're worried about any aspects of your health, get a "WOF'' from your doctor that gives you a licence to exert then start slowly by riding for about 15 minutes at a time about three times per week.
After two or three weeks, gradually ramp up your distances and exertion levels. You will get fitter and your skills and expertise will also improve.
Before too long, you will start thinking about tackling a decent hill, especially if you're riding a mountain bike.
It's only natural - that's why they are called mountain bikes.
Dunedin riders are especially lucky, as there are hills everywhere.
Pick your first big hill and away you go, probably in granny gear.
Top Dunedin mountain biker Jon Richardson says you shouldn't try to conquer the whole hill the first ride - see how far you get before your legs or lungs cry "enough" then take a break and enjoy the view.
One of our AOK Social Rider mottos is "We earn our views" and you will soon see why we say this, especially if you started from sea level.
Then strike out again and see how far you can get up the hill this time.
I find on big hillclimbs it helps to retreat into yourself and concentrate on maintaining a steady pedalling rhythm.
Don't look up the hill too far, as it can be disheartening to see how far there is to go.
The best big hills have plenty of corners, so you can concentrate on knocking them off one corner at a time.
Winding Castlewood Rd, just east of Macandrew Bay, is excellent for this sort of training and offers some great views as you climb.
If you practise your hill-climbing on the same hill each time, each time you go out you can try to get a little further than the time before.
Jon Richardson says you can even imagine a little reward as you grind up the hill - a good ride can be worth a slice of chocolate cake with that post-ride coffee, for instance.
And now comes the fun part.
What goes up must come down, and downhills are what makes cycling fun.
Experienced cyclists can top 100kmh on a smooth, sealed descent, which is incredible when you consider they're sitting on a small collection of pipes and thin rubber tyres.
If you're just starting out, you shouldn't even think about going faster than 50kmh or 60kmh, as you need to learn how to control your bike first.
On downhills, you need to concentrate intensely, alternating your vision from what's just in front of your front tyre to a longer view so you can spot any objects up ahead which might mean trouble.
You can use both front and back brakes, but be careful about heavy use of the front brake if you're turning sharply, and especially if the surface is loose.
Keep your body as still as possible and make all your movements smooth to avoid throwing the bike's balance out of whack suddenly.
Once you have cracked your first big descent, you may well stop at the bottom, take a deep breath, crack a huge grin and let out a yell - this is what cycling's all about.
You will now vow to ride regularly and build up your skills, and start studying maps showing fascinating places where you can ride.
You might even start riding to work so you can save money and get some sneaky training in ahead of your new cycling buddies.
If you are inseparable from your iPod earbuds or headphones when exercising, either learn to leave the little music-maker at home or stick to other sports. When riding on public roads, it's vital you know what other road-users are doing around you.
The wonderful Otago Central Rail Trail is an exception to this rule - except where it crosses public roads.