I used to work for a sub shop (when I was in high school) and they always proofed the bread, so I do this at home. I put a pan of water in the oven, and turn the oven on to 350, for 30 seconds (just don't leave it on longer, 30 seconds is all you need to warm up the heating element). THen pop your bread in to rise!
Just a warning, make sure you leave room for your bread to rise. I remember cleaning up a huge mess, when my bread rose and hit the rack above it. It was like a dough explosion! I was cleaning up dough for hours! So, just be sure to adjust your racks as needed!