i run a cycle commuting competition at work. it started off as one guy keeping a simple leaderboard between 5 of us. i took it over and turned it into "le Tour de National Grid Commute" and there are even prizes.
Maillot Jaune : most miles in the year
Maillot Vert : most trips in the year (introduced for those who had short commutes and couldn't compete on the miles
Maillot a Pois Rouge (polka dot) : fastest downhill sprint (no one likes climbing

)
Lanterne Rouge : Laziest rider
this year we have introduced our own colour for the person who climbs the most during the year. It's blue polka dot and is called the Maillot J'adores les Collines (i love hills jersey).
all our scores are kept on an excel sheet with stupid silly rules to keep everyone laughing. All mishaps and scores are logged and reported in each month in journalistic style. It's a great little competition and at the end of the year the company lets me have some national grid t'shirts and i dye them the appropriate colour to be handed to the winners at the celebration meal.
if anyone fancies giving it a go at their workplace and can send you my template. We even made the excel worksheet automatically work out the carbon we save per mile, so it's an eco-friendly competition too.