What is a fun dinner to make when you are bored on a Saturday night?

Pizza with a variety of toppings.

Macaroni and cheze

Chicken cacciatoria is pretty simple with only a little prep time. You can serve it with either pasta or polenta. The French analog is "sauce chasseur".

You, as in how many? Just myself, I like to make a stew of sorts. Lots of chopping and browning and by the time it's done you are easy to sit down with a glass of wine.
Couple, I like something with different components. I'll chop veggies while my husband browns up some short ribs. Chill for two hours, then have him braise some greens while I mash some potatoes and parsnips.
Kids too, make your owns. Pizzas, tacos, stir fries. I'll prep everything and portion for individuals. Then everyone gets exactly what they want.

risotto or stuffing chicken breasts with tasty stuff.

pasta carbonara because it'a fun to warch the sauce come together; the whole thing has just a few components and it goes pretty quickly.

Paella is a spanish seafood dish. Here is a very traditional recipe, though you can find hundreds of variations. It is time-consuming, but it is a great dish to make with others while sharing a bottle of wine.
http://www.epicurious.com/recipes/food/views/Seafood-Paella-366249

If you want to go to the grocery store: Paella......if not, homemade pizza.