Today, inspired by le Tour and my fellow cycling nuts on this thread I got out my trusty old Giant hybrid and cycled to work & home again. OK, it's only about a mile or so each way, but it's a start 
The first hundred metres or so are flat, then I make a left turn onto a very steep hill. I don't know what the gradient is, but it's long and very steep. I was determined to get up it, so I put the bike in the lowest gear and zig-zagged up. I didn't even get a run at it because I had to stop and wait while a dog owner recaptured her feisty Jack Russell who was trying to snap at my wheels.
After that it's pretty much all downhill into the village. Of course, on the way back it's a long, slow drag most of the way - then you get to finish off with a nice run back down the steep hill.
I've discovered muscles where I'd forgotten I had them - I run a bit so I thought I'd be OK, but no! It was good fun, & weather permitting I'll do it again tomorrow.