It's a significant effort to have students to your home, but it's a great way to have a more casual time with them, to get to know them in a different way. And they're so appreciative of a non-cafeteria meal and the chance to see a bit of your private life that that alone can be gratifying. Some faculty never have students over, and some have every class over every term. There is no necessary minimum (outside the required dinners with new first-year advisees). But should you choose to do it, here are some ways to make it a bit easier.
1) In the spring or fall, let them walk, even if you're a mile or two away--they can build camaraderie on the way.
2) If you tend to be shy yourself, schedule the dinner later in the term, so folks are already a bit comfortable with each other. But if you wait until the very end of the term--which is in many ways a logical time for a celebration--you lose the chance for a positive spin-off effect in the class.
3) Prepare food that can be made in advance and stored in the refrigerator or freezer so that little last-minute preparation is needed. Aim for one-dish meals (e.g., lasagna, stew). Or do things where the students themselves can do the assembly (tacos, pizzas on prepared shells).
4) Use prepared foods where possible without sacrificing too much the home-made quality of the meal. For example, HyVee makes up good shishkabob to order that can then just be stuck on the grill, and most of the grocery stores will also make up a tray of raw vegetables for dipping. Uncle Billy's Bakery has great desserts.
5) Ask ahead if any students have food restrictions (e.g. vegetarian, vegan, allergiees)--saves the embarrassment of someone taking only lettuce on their plate.
And be sure to save your receipts so you can reimbursed from the Associate Dean, who subsidizes all entertainment of students by faculty. Keep the expenses reasonable; the maximum reimbursed is $6.00 per person); no alcohol.