Large hotel corporations aren’t generally known for the pure-hearted promotion of good deeds – but Denver-based Sage Hotels (the chain’s portfolio includes select Marriott, Starwood, and Hilton properties) is an exception. Sage’s Give a Day, Get a Night deal rewards guests who have volunteered at least 8 unpaid service hours to a registered non-profit organization since July 1, 2009 with 50 percent off their first night’s stay – or, depending upon availability, a full night on the house – at any one of its 53 hotels nationwide. Valid for travels through March 2010 (the offer’s travel period was just extended 3 months), karma buffs can rest vindicated at a variety of properties ranging from full-service Marriotts (e.g. Chicago’s historic Blackstone) to luxurious Starwoods (like Portland’s The Nines).

Of course, there is some red tape. Only a limited number of free rooms are up for grabs, and reservations are required 2 days in advance. Upon check-in, guests must provide proof of volunteer work via an original letter (with official letterhead) signed by a registered 501(c)3 agency. To find out whether your charity qualifies as 501(c)3, click here.

See www.giveadaygetanight.com for booking info and a full list of participating properties.