And, so far, Studio 60 has avoided actual crossovers - though it looks like Sorkin might be pushed into marketing crossovers, with Masi Oka of Heroes appearing this week.
But now we have proof that Sorkin's two babies connect to each other.
Note the "Bartlet for America" poster on the wall in this screencap of a Studio 60 office.
Now if only we can connect to Sorkin's third series, Sports Night... then Tommy will have some new friends to play with!
ETA: Maybe it doesn't count? Discussion of Bush and 9/11 references in the comments...