I've used real life wooden puzzles and small chess-like problems in games before that the players had to solve to open chests or magic doors and such. Usually it was quite fun, as long as it is relatively easy to solve. The problem I faced was that sometimes players just don't see a solution. This is especially a problem with riddles (I've only used them ones and it was a disaster, even though the riddle was quite straight forward). In stories or movies you often see character quickly solving riddles and it seems quite fun, but in real life solving riddles is a lot less fun and sometimes you just don't get it and it can take ages.
Of course you can always decide to let the players roll dice to see if they get it, but that really defeats the point somewhat. Therefore I don't really use riddles anymore, since I find it just pulls people out of the game.