May as well continue the What, Who, Where theme!
When can you play Tabletop Games? Well that very much depends on the game and what available time you have to be able to play them. You also have to consider any prep time that a game may need. That prep time usually takes the form of "deck building" for CCGs and "army painting/construction" for War Games. These elements are very much a large part of the hobby for each of these formats.
How long do these games actually take to play though?
For the majority of CCGs a game take 45-60 minutes; this is based on a "best of 3" series of games in a tournament. Some games will take longer and some shorter as it really depends on how the games go but on average we're talking 45-60 minutes.
For War Games it depends on the size of the forces involved. For the majority of non-historical based War Games and in particular those that have a tournament scene the average play time of 1.5 to 2.5 hours.
When it comes to RPGs the length of the game is controlled by the players and the "game master". The average RPG takes 4 hours but some games can be completed in 2 hours whereas others last 6+ hours. As I said the length of time can be controlled by the players and the game master so in many respects it depends on how long they want to play for.
For everything else especially Board Games it really varies by the specific game played. These can be anything from 15 minute "pickup games" to 6+ hour epics.
So, finding the right Tabletop Game can in many respects be down to how much time you can spend playing it.