My ironic bathroom sink

My bathroom sink has a very interesting problem. It leaks. Well, that's not the interesting part. The interesting part is that it only leaks when it is not clogged. If you open up the cupboard below the sink and look at the P-trap, you'll find that there is currently a container under there, placed to catch the leaks that happen whenever I use the sink. Happily, the leak is rather slow, but if you listen after running the sink you can hear the characteristic "drip drip drip" that means the water is draining from the P-trap into the container below. Oh, and by the way, it only started leaking yesterday. Why yesterday, you ask? Because overnight I put some hair clog remover down the pipes, since the sink was draining quite slowly. Apparently whatever gunk and gook was clogging the pipes was also plugging whatever small hole the leak is coming out of. So, theoretically, I could wait for the sink to just get slow again and my problem will be solved! Or I guess I could eventually go down to Lowe's and buy a new P-trap... but it seems like it would kind of ruin all the fun. :)