To keep indoor cats entertained, you can try the following tips:

1. Provide a variety of toys such as interactive toys, laser pointers, puzzle toys, and feather wands (only when you’re playing with them), to keep them mentally and physically engaged.
2. Create a designated play area with scratching posts, climbing trees, and hiding spots.
3. Rotate their toys regularly to keep them engaged and prevent boredom.
4. Use food puzzles or treat dispensing toys to provide mental stimulation during feeding time.
5. Set up a cat window perch or bird feeder outside a window to provide visual stimulation.
6. Play with your cat regularly to bond with them and keep them active.

Remember that every cat is unique, so it may take some trial and error to find the activities and toys that your cat enjoys the most.