Some like cutting things out - tends to be more at age 3 and 4, though some 2 year olds can use scissors.
Drawing: Cover a table fully in paper. Get some cars and draw on roads. Stick crayons to side of a truck and let them drive it around, making marks as they go.
With walking, try to find somewhere that they can be on their own, walking say 8-12 feet in front. I live near Windsor Great Park, so that's ideal to give children some freedom to roam. They soon get used to commands such as Stop, Wait, when they get too far ahead.
Oh yes, running around the house - though not great to encourage that one. Indoor play type places are good for that, large halls/sports centres.
Farm Animals, Dinosaurs, Monsters, Robots - that kind of toy. Soldiers, Castle. They can be quite imaginative when playing with these things... sometimes I have no idea what the game is!
Cooking can be a good one, but they tend to loose interest very quickly. It's the stirring things around they like.
Pots and Pans with wooden spoons make good musical instruments. Took a 4yr old and 1 yr old to a museum last week - at the museum they had musical instruments with a hands-on area. The boys loved bashing the drums! Horniman Museum, Forest Hill, SE London
Taking things to pieces is something a lot of boys like doing. I remember doing a lot of that when I was little. You can get toys especially which come apart, build with bolts - Build&Play Car - BuildIt Construction.
Though of course an old remote control, or some other bit of technology, is so much better to take apart - even if a bit more dangerous!