Anything that goes unused can be bought online, from concert tickets at StubHub to wholesale bricks at Craigslist (now with more brick!). Now for sale: unused restaurant reservations, at TableXchange.
Just now in LA, TXC is a clearinghouse for hard-to-get tables (Spago, STK, The Mozzas...), posted by people just like you, only better, because they scored a reservation without paying for it. Just search by restaurant/date/party size, then purchase the reservation by credit card; you'll receive an email with the original reserver's name to use when you check in, a system that'll give some lucky bastard the chance to become the first African-American "Finklestein". Prices come in $5 increments, with most currently set at $10-$15 -- a mere appetizer at a place you'd be tempted to use your corporate card, or several entrees at the pit you'll be consigned to after abusing your corporate card.
Sellers can also include notes, both private ones readable only after purchase (for confirmation numbers, etc), and public ones that serve as enticements, or explanations for why you're giving up your seats, e.g., "Watching the Lakers with guy who sold me bricks".