I went to Puerto Rico with my wife for the wedding of her best friend's son. It was a big wedding and they had it covered with 2 photographers and a crew of video shooters so I just took pictures more for me, some of which I will put on a CD and send to the newly weds.
Anyway the reception was in a super dark room mostly lit with colored spot lights, neon like lights and candles. So I took a lot of pictures using my 85mm 1.2 lens and set the ISO way up to like 12,000!
So here are 2 examples of the shots I took and some blown up details just to show how amazing the Canon sensor in my camera is as well as the lens although the depth of field was very slim. I was impressed!