I can totally relate! We live in a small, carpeted apartment and my son, who is now 3.5 yrs., still isn't interested in crafts 99% of the time. He has a LOT of energy so keeping busy and engaged is my primary job. We go out everyday, whether it's to a playgroup, play date, park, visit with family, museum, local farm, hike in the woods. Anything and in any weather. Here are some things we do inside:
Sometimes I break out the crafts boxes and do it myself, I find that even though he's not interested he'll gravitate to the table and play near me and give input on what I should do. I draw pictures and he tells me a story to go with them and I write it on the back of the picture.
Two crafty things he does do regularly are 1) use play dough, which usually is just mashing it and poking at it with tools more than making stuff, and 2) finger paints with his feet. (I keep a large trash bag ripped open for a "safe area" do to messy projects.)
Another crafty thing you can do if he likes playing with cars and trucks is get some large paper and draw a map for him to drive them on. He tell you if he'd like a city or construction site or jungle and help pick out where different things should be.
Fill the sink and let him play with kitchen utensils.
Break out some baking soda and a scrub brush so he can help clean the tub. My boy came up with this on his own one day and it's so great to get some cleaning help.
Our local library is super important to us. If he has a question or interest in a topic we go and find books about it. That usually inspires us to do another activity related to the original question and engages more play. He also loves listening to stories, sometimes I just read for 2 hours if that's what he wants to do.
My husband used to have a large plastic box filled with plastic pellets (which you could substitute with anything from rice, beads, beans) for an ad hoc sandbox that was easy to clean up after. I bet an under bed storage box would be great for this since you could just put the top on it and tuck it away when you're not using it.
In reality, 90% of play time for us is with cars and trucks. I'm looking at my living room and there's at least 20 of them all over the place as I type this and he's playing with one on a road bridge telling a story to himself. This used to bother me because I thought it was limiting, but I've come to realize that they are his version of dolls. He makes up stories, he stacks them like blocks, he lines them up, we make garages out of them and figure out what the best size will work for the vehicles we have out, we count them, we compare their features and colors, they talk to each other. All the things we want to encourage in imaginative, learning play time. So look at what your child likes to do for play and draw your inspiration from there.