I love sliders! I know, no surprise since I'm partial to small food, but these are fun to make plus you get the opportunity to try lots of flavors instead of one type when its a full size burger.
We grilled 4 types of sliders this weekend for some friends and I think it was a hit! The sliders included beef with tex-joy seasoning,
southwestern turkey, pork/chorizo (adapted from
here) and buffalo/blue cheese. We also had lots of toppings including cheddar and pepper jack cheese, lettuce, tomatoes, guacamole with bacon, bacon, onions sauteed in bacon fat and others. (See a trend there?)

Other slider recipes:
chili bowl burger sliders (I'm still on the fence about the shaping of meat into a bowl form but I like the idea of chili-like spices in the meat itself)
meatball sliderslamb sliders (on potato rounds instead of buns)
white castle style slidersturkey sliders with feta and sun-dried tomatoes