I want the Corsair Spec-01 mid-tower PC case, with the Asus H81M-A Micro ATX LGA1150 Motherboard. The case has two front-facing USB 3.0 ports. However, my motherboard only has USB 2.0. I realize I wouldn't get 3.0 performance, but if I hooked them up, would they work, even with USB 2/1.0? This is my first PC build, so I would appreciate some explanation on how these things work, along with a concrete answer.
Your case front panel likely has a standard 20-pin plug, with cables to two front panel USB 3 receptacles. To interface it with the on-board 10-pin USB2 header, you would need an adapter like this one: https://www.amazon.com/Neewer-Female-Motherboard-Adapter-Converter/dp/B009SJCPO8
The adapter connects only USB2.0 wires, and leaves USB3 set of wires unconnected. When a USB3.0 device is plugged in, it won't find expected termination on loose wires, and falls back into USB2.0 mode.
ADDENDUM1: If you would like full USB 3.0 functionality from your front panel, there are 4-port PCIe controllers, two ports on back, and 20-pin header internally, where you can plug your front panel directly. http://www.ebay.com/itm/like/252408075871?lpid=82&chn=ps&ul_noapp=true