The last time I went to a potluck dinner, it was held immediately after the dress rehearsal for a musical in which Ten was performing. I was assigned to bring baked ziti. There was a lot of planning ahead of time regarding how to keep the ziti hot.
That planning was successful. Here's how I did it: I brought a pound of cooked, cooled pasta in a ziplock bag, with a couple of tablespoons of olive oil to keep it from sticking together. Another bag held a pound of cooked ground beef; still another bag had 2 cups of shredded mozzarella cheese. I brought about 3 cups of spaghetti sauce in containers.
When I arrived at the party location, I lined my slow cooker with a slow cooker liner. I added the pasta, meat, cheese and sauce a little at a time, stirring after each addition. Then I turned the cooker on high and let it heat the food for 3 1/2 hours, stirring once in the middle of cooking.
And that all worked great. Everything was hot and ready to eat at mealtime. The problem came when I had to deal with the leftovers.
I gathered up the ends of the bag and tied it with a stray twistie-tie I found on a table. Then I picked up the bag and popped it into my cooler, which had some ice packs in it.
That was a big mistake. The seams of the bag gave out and there was pasta all over the bottom of the cooler.
Those cooking bags are great for cooking and they keep the slow cooker clean. Unfortunately, I can't say the same for coolers. I don't think it could handle the temperature difference! The cooking bags go from cook to serve, but not to store. (To be fair, they're not advertised for the purpose of storing food; it was my own improvisation that got me into trouble here.)
I use my slow cooker a lot in the summertime, because the oven heats the house up too much. If you're looking to expand your collection of cookware this summer (grill pans, anyone?) check out this great sale at Sur la Table: through July 5, you'll save up to 60% off Summer Clearance items!