Pulled pork, glazed ham, pepperoni, brisket, and salami pizza (with BBQ sauce, of course). I've only ever been to one place that does it - now closed, sadly - but by God was it bloody amazing; even if it probably did take five years off my life.
In addition...
Thai sweet chili sauce - on everything. Goes particularly well on just about any sort of Mexican food - turns tacos, burritos, and enchiladas into something new and amazing. Also goes good in chili, and on more mundane things.
Also...
Tuna sandwiches with a cup of tomato soup on the side. Delicious.