That depends heavily on the resolution, audio quality, and compression quality. A quick search turned up this calculator that might help you: http://www.digitalrebellion.com/webapps/video_calc.html
Some high-resolution uncompressed formats would fill such a memory card with less than 2 minutes of video, while low resolution and aggressive compression would allow about 476 minutes to fit.
If you're using an HD camcorder (1920x1080 at 29.97 fps), then the bit rate for high-quality recording is typically around 20,000 Kbps, essentially 2.5 MB per second. 32 GB is 32,000 MB (it's not 32,768 as it's an advertising gimmick) so that means about 12,800 seconds or 213 1/3 minutes. So, you can expect something from about 180 to 240 minutes on a 32 GB card. With a quantizer-based bit rate (rather than average), limited motion, and other such things, you can expect a lot more to be available.