How I Met Your Mother joins the FX line-up starting Monday, Sept. 5, 2011 with a Labor Day Marathon to kick-off its FX premiere! The marathon will air from 12 noon to 12 midnight. The series will then join the schedule the following day.

http://blog.sitcomsonline.com/2011/07/fx-fall-2011-schedule-has-how-i-met.html