Yet another view of the chaos in Oakland on January 28, 2012 that ended with over 400 activist's arrests.
The person who posted the video to Youtube left the following note:

Armed Riot Cops in Oakland Ca. kettle 300 Occupy Oakland protesters before an occupier with a membership card gets 100 people inside the YMCA. Riot cops swinging batons flood the area and seal off the YMCA. Terrified Occupiers scatter looking for a way out while cops use urban warfare tactics with guns drawn to hunt them down amongst gym members working out. The last 10 who escaped advanced just ahead of the closing OPD. 24 people inside were later charged with trumped up felonies and tortured in the Santa Rita jail for 4 days. Welcome to America!

I couldn't see any drawn weapons, but you only get a glimpse of the police inside the YMCA. At the start of the video you can hear the terror in the protesters voices as you see the Oakland Police charging up the street towards them. They're pleading the the employees of the YMCA to let them in, and then people working out inside quickly exit.