When my buddies and I get together on brew days we always partygyle! We took the second runs from a milk stout, an IPA, and a belgian tripel, and got a decent 5.5% dark ale. It wasn't necessarily to style but hey it's free beer and it's pretty good too. We also ran seconds on my graham cracker ale and an "amaretto sour" beer and made a dark Kentucky Common. We have done a few others and haven't tried them yet. They always turn out good even if not to style. The trick is just to start kind of early and not to drink too much on the first batch. If you expect it to take all day you wont be disappointed. A little planning goes a long way too. Take your second runs on a belgian strong and make a belgian pale or even an american pale ale and hop it up.