Use empty water bottles, tissue or paper towel centers and a ball to go "bowling". Or use small paper lunch sacks - number them, set them up and let the boys try and knock them down with a ball.
Make bean bags out of old sock, rice and secure with a rubber band. Try to get the bean bags into a large basket or onto a pillow case or for more of a challenge, onto a piece of printer paper.
Cut out the shape of a leaf. Put a bean bag under the leaf and throw it up in the air (try and hit the ceiling if you can), the bean bag will come down fast and the leaf will float down. Have the boys take turns trying to catch the falling leaf. It's great fun and really good for the hand-eye coordination. Make sure you clear all the obstacles from the immediate area so nobody looses a tooth or blackens their eye while watching the falling leaf instead of the end table.
Make a feely box out of an old kleenex box. Put toys or wooden shapes or play food, or wooden letters, etc. and have them take turns feeling the object and guessing what it is.
Fill an ice cube tray with water. Color 4 of the water cubes with dye using only the primary colors. Let the boys use medicine droppers to experiment with mixing colors in the remaining water cubes.
Pretend to be at the circus. Put a strip of masking tape on the floor and let the boys take turns pretending to walk the tightrope. Have them do it different ways... forward, backward, hopping, balancing small objects in the palm of their hands or for your older one balancing on the backs of the hands.
Hope that helps. And I'm not on this site to push my book. If you see my profile, I do enjoy being a part of this community for the wisdom women share with one another. However, if you'd like more ideas like the above, I have a book called Kitchen Table Play and Learn (Amazon). It's a book of 30 thematic lessons which include academically enriching preschool activities and crafts that parents can do with their children. As you can see, it's also good for a rainy day! You'll have to modify much of the above and what's in the book for your little guy, but he can certainly have some fun too.
Enjoy!