Take action, especially following a time of indecision or delay. For example, It's time this administration got off the dime and came up with a viable budget. This expression originated in the 1920s in dance-halls as an imperative for dancers to get moving. By 1926 it had been extended to other activities.

The American Heritage® Dictionary of Idioms by Christine Ammer. Copyright © 1997 by The Christine Ammer 1992 Trust. Published by Houghton Mifflin Company. All rights reserved.