Some get the dogs excited and running wild, a bit too much for indoors.
Start slow at “find it”, with something you cover with a towel, then hide under pillows.
Work up to when they are good at searching for something, put them on a sit and go in another room to hide stuff, then release them to “find it”.
Try to mix games where you are still and they have to do something with others where they have to be patient and still, static ones.
We used to go to the basement to train in obedience and the dogs lived for that.
It made their day, the basement was magic to them.
We had a smallish round rug there that was “place” and they got extra treats there.
They ran down the stairs to it and would do a series of sit-down-sit-down-sit … and then get a jackpot.
We tried not to do any non obedience tricks there, like roll, shake and such, so they would not do it at an obedience show, like on a long sit, when someone walked by, start offering behaviors, like, “are you ashamed” (paw over nose, taught today with clickers, before that with a piece of scotch tape they pawed at), shaking hands or waving “high fives”.
Don’t forget to work up to have them use both paws for each exercise, turn both ways for those that ask for turning, like spins, roll, etc.
You can make a spare room you keep closed otherwise the interesting place where good stuff happens.
We trained all the time for stuff we would do in school and library demonstrations, that was done generally indoors and in small spaces, so working indoors was where we trained much of the time.
Even in agility training you can do some of that indoors, using furniture and broomsticks.
All our dogs learned “table, sits and downs, pause to a count and go!” on different coffee tables.:yes: