Hi there - it can be hard finding things for them to do when the weather is bad, so I commiserate!!
My little man loves painting... I put a big plastic sheet down on the kitchen floor, pop his little easel in there and he'll paint, colour, chalk you name it away to his hearts content! Sometimes we just put the paper down on the plastic sheet and do hand and feet prints (got to make sure you have a flannel handy for a rapid clean up for this one though so you don't end up with "art work" all over the house!!!)
Play dough is another popular one in our house - he'll spend hours "cooking" with playdough , cutting out shapes, playing with the different playdough toys and accellories ( there's heaps of them in the shops!) or you can just give them your baking things and a few tupperware containers and they'll play for hours!
Building blocks... they love you to help them build big towers and houses etc...
Teddy bears picnic - Quinn will pop all his teddys on his table and chairs and we have to give them all plates / spoons and feed them.
Water play - again, plastic sheet on the kitchen floor and a basin of water and some water toys...they'll play for hours! Will be messy though, so have towels etc at the ready and don't leave them on their own. Sometimes I put a few drops of food colouring in the water and we have pink or green or blue water - they love it and it won't stain anything!!
Music and dancing.... little man loves the Wiggles so will dance around to their stuff for EVER. Apparently it's even more fun when Mum joins in !
Baking - Quinn will "help" me to bake... it's very messy, takes 4 times as long but they do enjoy it!
Hopefully some of those ideas will work!!
It's Summertime here at the moment, so I'm enjoying being able to send him outside for the majority of the day - but I know it's only a matter of time before he'll be stuck inside again and I'm not looking forward to it!!!