You can roast rutabagas (which are not the same as turnips, IMHO). I cube them and roast them along with other root veggies like sweet potatoes, and with winter squash. The rutabaga is denser, so I usually cut them into slightly smaller pieces so that everything cooks in the same time frame. As much as I love roasted veggies, I still prefer rutabagas boiled and mashed.

Turnips are smaller than rutabagas, and are never waxed. Rutabagas are sweeter than turnips, and are actually a cross between cabbage and turnips.

That said, my first husband, who came from Lynn, insisted that rutabagas were turnips; so clearly it's a regional distinction.