You might want to clarify what you mean.
Settings
Martin,
i keep getting games and I cannot keep up with them all. I am currently playing 13 games. I only want to play 2 or 3. How do I say I don't want to play any more at this time?

There's an option somewhere in the settings to block upcoming games/challenges (although I've never tried it myself) so that you can only select which time or games you are open to invitations..that is if that's what you mean by your question. If not, sorry to disappoint you.
How do I stop "Inviting" people?