Tapas in Madrid are usually eaten before lunch, at “vermut” or “aperitivo” time. This can be done before lunch or after work.
Apart from eating the Madrid tapas and drinking sangria or beer, these bars are a good place to watch football games and people get together for the occasion; specially when there is a FC Madrid vs Real Madrid game.
It is also quite popular to have tapas in Madrid for dinner. Groups of friends like getting together and sharing some tapas at a good price. It's a budget dinner and it is fun to choose which tapas to eat and taste different Madrid tapas.