Adam Neely and his band Sungazer did an interesting live experiment with his audiences, to figure out the slowest beat or pulse that people would be able to "feel" and dance to. Slowest possible isn't really as interesting in my opinion as slowest practical, which I think Neely and co's experiment explored. The track was Threshold on the album Perihelion.

The whole album explored beat, pulse and timings as it relates to how people can actually feel and interact with music. Really interesting!

is that also the album/live shows that had the audience dancing to the beats 1,2,3,4 which they thought was 4/4 but in such a way that the underlying time-signature was different?