If you plan to use the subway on the weekend, be prepared for significant deviations on some lines, usually due to construction. For example, an express train might go local, or vice versa. Among lines that are grouped together (e.g. the 1-2-3, or the N-Q-R-W) you might suddenly find that train x is running on train y's route. Sometimes, a train will run on a completely different train group's route (e.g. for a while, the 2-3 was running on the 4-5-6 route on Sundays). Sometimes trains skip stops as part of the weekend fun. We have had several frustrating and confusing experiences since we moved here, including a Saturday afternoon when it took us 90 minutes to get from Union Square to Battery Park (a trip that normally takes 10 minutes) because we kept detouring over a bridge into Brooklyn because we hadn't cottoned on to the fact that our usual train wasn't planning to go along its usual route. There are signs in the station, but often there will be about 20 of them, so it can be difficult to figure them out. As others have mentioned, you might have difficulty understanding the advice of the station staff in the booths - and the PA announcements are in Martian. If you carry a Blackberry or something similar, you can sign up for travel advisories from the MTA website and you'll get a list each Thursday of what the planned closures and deviations are for the weekend, which will help a little for planning purposes.