Ever wanted to dance wildly in public surrounded by a group of dancing strangers? Well now's your chance. As part of WBEZ's Five to Five Challenge, the station will receive $1,000 from an anonymous donor if we can assemble a group of people to Mass Dance tomorrow afternoon. We'll meet at the Millennium Park Bean, wearing ipods equipped with this song: song Then, at promptly 5:30, we'll switch on the song and dance like crazy. The weather's going to be great -- warm, sunny, no rain -- so there's no reason NOT to be in beautiful Millennium Park. Invite your friends! We've got a second $1,000 on the line in our Snap Spot Flickr contest -- just nine photo uploads to go and the station gets $1,000. Deadline is the end of the day Friday. Upload some photos and show us some love! Here's one of our favorites so far. The most interesting photo wins kitty's stylish WBEZ tee.