What are your favorite fun and inexpensive activities to do on a Friday night in San Francisco?

I am looking for a new thing to do on a weekend night with my boyfriend in SF that doesn’t cost a lot and is different. I am getting sick of the typical nights of either movies or drinking. I have recently stumbled upon this list: http://sanfranciscoissexy.com/2008/10/14/60-super-sexy-things-to-do-in-san-francisco/ which seems awesome!

Is there any particular activity you have found in the city that is different?