Looking for something to do tonight or tomorrow? Arsene50 might give you some affordable options. This service offers tickets at about half price for shows (theater and movies mostly, also some museum exhibits and concerts) the same evening.
Which shows? You can check the list of available shows every day online (or sign up for the weekly newsletter, which gives you an overview of the tickets available for the upcoming week).
How do you buy the tickets? Two options: (1) get them at the box office on place Royale (BIP Visit Brussels office on 2-4 rue Royale) between 12:30h and 17:30h from Tuesday to Saturday or (2) buy them online between 14:00h and 17:30h on the day of the show.
Tips: You have a better chance of getting the tickets you want if you go to the BIP office because they start selling tickets sooner. Besides, since the office is closed on Sunday and Monday, on Saturday, you can already buy your tickets for shows on Sunday and Monday, in addition to Saturday.
I tried this service recently and it was extremely easy to use. There was almost no line (just one person before me), chose the show (Terracotta warriors exhibit at the Bourse), paid for the tickets, and got the voucher, which I could then just use as a ticket at the venue. (Note: in some cases, you have to exchange the Arsene50 voucher for a real ticket at the venue’s box office, so you need to arrive a bit earlier).
For today and tomorrow, there are still some show and movie tickets available for purchase online… Enjoy!