You could also see what you can get for them on Points.com. Some FTers do not like Points.com for reasons that are various and, for them, valid. Others, like myself, do.

You can exchange them directly to another program. Not all programs allow this, and the exchange rate generally is, erm, lousy, but you can do it.

Or, offer them up for trade for a program you do use. Again, not all programs allow this, and there is a trade fee on what you're giving up. For most programs it's 1cpm to trade. Some people object to paying the fee, but if you're not using them and someone's offering a trade that you consider a good proposal...

You can also redeem them for various gift cards. Like exchanges the rate is not terribly great (4k generally doesn't get you much) and not all options will accept Frontier miles, but it's free.

If you want to postpone their expiration, you can exchange some points/miles into Frontier. Most programs have minimums to exchange out of them, but US Airways doesn't. 5 US miles gets you 1 Frontier, which is enough to extend it two years.

Here's a thought: save them for this year's US Airways Grand Slam (if there is one this year, not confirmed yet). In last year's GS you got a hit for exchanging points into DM, and if you're not using them for something else.....and you can always do something with them later.

Though donating them is still a top-notch idea. ^