Tool's "Schism"
From Wikipedia:
""Schism" is renowned for its use of uncommon time signatures and the frequency of its meter changes. In one analysis of the song, the song alters meter 47 times.[4] The song begins with two bars of 5/4, followed by one bar of 4/4, followed by bars of alternating 5/8 and 7/8, until the first interlude, which consists of alternating bars of 6/8 and 7/8.
The following verse exhibits a similar pattern to the first, alternating bars of 5/8 and 7/8. The next section is bars of 6/4 followed by one bar of 11/8. This takes the song back into alternating 5/8 and 7/8. Another 6/8 and 7/8 section follows, and after this the song goes into repeating 7/8 bars.
The middle section is subsequently introduced, consisting of three bars of 6/8, one bar of 3/8, and one bar of 3/4 repeating several times. At one point it interrupts with two bars of 6/8 followed by a bar of 4/8, twice. A bar of 5/8 is played before the meter switches back to 6/8 for two bars and 2/4 for one bar. This repeats, setting up another section: two bars of 9/8 followed by a bar of 10/8, that pattern again, and then a single bar of 9/8 followed by alternating bars of 6/8 and 7/8. The outro has alternating bars of 5/8 and 7/8, ending with alternating 6/8, 2/8 that one could interpret as pulsing with a 4/4 feel.
The band has referred to the time signature as 6.5/8.[5] Although many composers would use 13/16 instead, 6.5/8 is still a valid fractional time signature."