My new toy
... is a cycle "computer", so-called, although that's a rather grand term for a £7 item that works on the simple principle of a magnet on a front spoke passing a detector fixed to the fork. You tell it the size of your wheel; it works out how far and how fast you've gone.
But the "speedo" as I prefer to call it (that means speedometer, for those who need the translation from Australian) has provided me with hours of amusement.
First, it allowed me to calculate the shortest route for my new commute - 6.7 miles home from South Quay, through Shadwell (on nights when I'm feeling brave - I've only had a rock thrown at me once), past Bank Tube, then along New Oxford St in the bus lane and straight up Tottenham Court Road.
The longest option is around the Regent's Canal (daytime only of course), which is 8 miles - I keep meaning to do it, but it does take about 10 minutes longer and I live in a perpetual condition of running late, so I seldom get to it. (In fact I've done it once, but the wild birds etc were lovely, and I must do it more often.)
Second, it has allowed me to check my top speed, which until the weekend was 16mph. About that point in London I start getting nervous about stray pedestrians, dogs etc and my stopping distance, but on the weekend adventure I actually got up to 22mph! Yes I know that's standing still in serious cyclist terms, but it felt pretty fast to me - and the bike felt about as unstable as I fancy, for the moment anyway.
So, my recommendation is: if you've got a bike, get one of these! (In fact I regret not lashing out on one of the more expensive ones, which have a tripmeter. Mine is only cumulative, so you have to remember the starting distance on each journey to calculate its length.)