Here's another way to experiment if you've got a bunch of marinades or rubs you want to try out - make kebabs.
I recently got a bunch of Steven's rubs and spice pastes from his new Planet Barbecue line, and I wanted to try them out. The problem was that I was a bit short on meat and I was cooking for one so cooking up a whole bunch of meat was out of the question.
My solution? I skinned and deboned a bunch of chicken thighs and cut them in half lengthwise, then marinated a couple of strips in each marinade. A few hours later I threaded them on flat skewers and cooked about a dozen kebabs - two with each spice paste (8 in total) and four individual kebabs with one of Steven's new rubs apiece.
This was a really good way of testing a number of rubs and marinades at once, plus I had a few extras for lunch the next day.
Incidentally, if you get a chance to try Steven's new Planet Barbecue marinades and rubs I recommend you do so. His Malaysian spice paste is excellent on chicken and pork, and his Jamaican paste is the best commercial jerk marinade I've ever tried (and that's really saying something).