For these kinds of images, I would just aim the flash right at them and nuke 'em! These are not portraits, they are not art, they are just a recording of people at an event. Even the hard and harsh light from direct flash is better than this.

If you are going to do this on a regular basis, get a stroboframe flash bracket of similar, get a TTL cord for the flash and then get the flash up above the lens by 8-12" and attach something like a small Lumiquest softboxIII. YOU get direct flash but the height kills that red-eye (to a degree), and the height makes it a bit less direct, and the soft box gives you 15 to 30 times the area so it is a bit softer. I do this for events in dark areas all the time.

Here are two examples from a heavy equipment trade show in a dark convention hall. Nikon D700, ISO 400 1/60 @ f/3.5 with the strobe frame bracket and a Lumiquest SoftboxIII using a Nikon Sb800.

Piece of cake.

In low light events, I don't use my flash in the bounce mode. Most of the venues I have attended haven't been conducive for effective bounce.

I take it off camera and shoot hand held, usually on an extended arm to get it higher and closer to a 45 degree from the camera. I have different diffusers that I put on the flash to soften the light, depending on the look I am after.

Sometimes wired and sometimes I use the Pocket Wizard flex units, either maintains ETTL so I can dial in compensation on camera.