I know you are doing burgers, however I am a fan of the
Impossibly Easy Cheeseburger Pie.Real simple. You can substitute ground chicken or turkey with ease, and leftovers are awesome. It goes well with a salad with raspberry vinaigrette, and you can also do sweet potato tater tots or fries.
I also am a fan or the pork loin in your grocers refrigerator case. I usually wrap in in foil, fat side up and throw it on the grill. The fat constantly bastes the loin, and it comes out super juicy. While you got the grill goin, may as well do some garbage potatoes. get some small taters, or cut up bigger ones. I like to use yukon gold, fingerlings, and purple potatoes. Again, bust out the foil,throw the 'toes, olive oil, garlic (i like lots), maybe some green beans, really anything that may tickle you fancy. I throw a lot of cloves in there, and when you grill em, they become soft and delicious, like a healthyish pad of butter.I could seriously eat just straight grilled garlic. It isn't as strong as raw, and it is just fucking great.