Thought last year's urban zip-line in Justin Herman Plaza was cool? Try rappelling 36 floors off of the Grand Hyatt rooftop, right down into Union Square. Seriously. This Friday and Saturday (July  22-23) you'll have the opportunity to do just that at Over the Edge, an adrenaline pumping fundraising adventure, benefiting the Special Olympics of Northern California. Last year, Over the Edge raised $100,000 and, this year, they're looking to seriously up that number.

What's the catch? To participate, individuals must raise at least $1,000 for the SONC, and hurry because only the first 100 people get to rappel. Raise more, get more -- $2,500 earns a one night stay at the Grand Hyatt SF during the event, and $5,000 earns a free trip to the Las Vegas Over the Edge event this October. 

There's no age limit to participate, but rappellers must weigh between 110-300 pounds. For full details, visit the Over the Edge website. 

Over the Edge at the Grand Hyatt (345 Stockton St.), Friday July 22 from 1pm-4pm, Saturday July 23 from 9am-4pm.