1) Having all the players of the NFL and all the players of Major League Baseball switch sports for one season, so we could determine once and for all if baseball players can play football better than football players can play baseball.
2) If the outer reaches of DC's Metrorail system connected with the outer reaches of Baltimore's, to Philadelphia's, to New York's, so you could basically take Metros and subways all the way from DC to Manhattan without leaving the system.
3) Helicopter shuttles leaving from various nearby office buildings that could take you to the local airports.
4) Festive holidays at the end of winter instead of the beginning, so you'd have something to look forward to during all the cold.
5) Living upstairs from a bakery that serves beer and good pizza as well.
6) If the best actors in history were cryogenically frozen in their prime, so eventually we can see that Kevin Bacon/Laurence Olivier film we always wanted.
7) If just once the president would leave some background radio music on when he gives some address from the Oval Office, so everyone can think "hey does he know he left that radio on?"