Preheat oven to 190ºC (375ºF). In a small bowl, stir together brown sugar, chili powder, cumin, pepper and salt; set aside.
Cut acorn squash in half along ridges. With large spoon, scrape out and discard pulp and seeds. Cut each half into five wedges. Place wedges in a large bowl. Toss with oil and half the brown sugar mixture.
Cut bacon slices in half. Wrap each piece around the middle of a squash wedge. Place on parchment-lined baking sheet, with ends of bacon slices on underside of squash wedges. Sprinkle with remaining brown sugar mixture.
Bake 25 to 35 min., turning over halfway, until squash is tender and starts to caramelize and bacon is golden. If bacon browns before squash is tender, tent baking sheet with foil and continue baking.
These squash wedges reheat perfectly. Bake them up a couple days in advance, store in fridge. To reheat, place in parchment-lined baking dish or on baking sheet. Cover with foil and bake 10 to 15 min., until heated through; uncover and bake and other 5 to 10 min.
Substitute butternut or delicata squash for acorn squash.