My DS is three. He's really into tracing letters, watching certain DVDs, baking cookies, making toast, certain puzzles, moving his cars around, playing with trains, playing catch or keep away, coloring on a magna doodle, thomas the train apps, and bo the giraffe apps, playing the piano, organizing a band, making the beds, folding the laundry, going to the grocery store/ coffee shop/ bagel shop, watching the trains, taking the subway or bus.
At his age, it's pretty hit or miss, that thing which kept him contentedly occupied for 1/2 an hour today, might not hold his interest tomorrow.
I say have plenty of options and by all means take them out.
Best,
F. B.