This looks like a blast. You don't really need to be much of a biker either. It is 18 miles around San Diego Harbor. The cost is $30 pre-registration, $35 the night of the event. Check out some of the links below.
Note: Front and rear lights are required.
Looks like the best way to go is to register early and get your bib in the mail to avoid the hassle at the event.
Hostelling International USA, San Diego Council is proud to announce the 37th Annual Midnight Madness Fun Bicycle Ride. We ride at midnight! The cycling route is a primarily flat 18 mile loop, along some of San Diego’s most beautiful waterfront and historic areas. Don't forget to dress up in your wildest costume and light up your bike with a light display to win fabulous prizes!!! Ride will be limited to the first 2,000 participants