It's a great way to get people onto bikes but also to get them to develop the habit.
The only rule for 30 Days of Biking is that you bike every day for 30 days—around the block, 20 miles to work, whatever suits you—then tweet about your adventures with the tag #30daysofbiking. Event starts on April 1 and ends on April 30!
Go for it!
Thanks to Kelly for the link.