What comes after 611? 711.
What comes after that? 811.
What comes after that? George W. Bush.
Listen up, buttercup. This joke is playing on how after 9/11, everyone was all about George W. Bush, right? Like, he came right after 9/11 in the nation's consciousness. So, the joke is that after 611, 711, 811, the next thing that "comes" to mind is Bush because of 9/11. And you, my friend, probably still use training wheels on your brain.