Under NFL rules, the same team cannot call consecutive timeouts. If the officials incorrectly acknowledge the consecutive timeout, the clock is immediately started and the timeout negated. There is no penalty for this act, unless the purpose of the second timeout is to startle and cause a false start by the offensive team. In this situation, an unsportsmanlike conduct foul could be called on the defensive team. Under college rules, consecutive team timeouts are legal, and a team could call all of the team timeouts in succession.
When the penalty was called I googled this immediately. This is in reference to a Colts-Bears game in 2005 when the Bears tried to call 2 timeouts in a row. Seems the unsportsmanlike conduct call is a judgment call. Its not an unsportsmanlike penalty for trying to call a timeout you don't have, so this ruling is baffling to me.
Here's the link.
Jerry Markbreit's answers on ChicagoSports.com