Time signatures convey important information for performers. The notation indicates how many beats are in each measure and the value of one beat. For example, one of the most common time signatures, 4/4, means that there are four quarter-notes per measure. Other common signatures include 3/4, 6/8 (six eighth-notes per measure), and 12/8.
Of course, sometimes these frequently used signatures are insufficient when conveying more complicated musical ideas. Complex time signatures, like 5/4, and other less common signatures are valuable to express more challenging meters, in which rhythmic patterns change. 5/4 could be read as (2+3)/4 or (3+2)/4 depending on where the stressed and unstressed beats fall. A well-known notorious example is the theme from The Terminator, which uses the time signature 13/16. In that example, the rhythmic grouping is 3+3+3+2+2 (or: 1-2-3 1-2-3 1-2-3 1-2 1-2).
What are some other examples of unusual time signatures? Here’s a list we came up with. What did we miss?