Cookie I dont think you have to worry. Its impossible to entertain a baby all day long.
K enjoyed her play gym at this age and they start learning to grab things so putting toys close by that they can try and hold.
You can also start sitting him in a bumbo around now although he may still be a bit floppy.
And they keep themselves amused, they take everything in so just being in a room with you he wont necessarily be bored and you'll drive yourself crazy trying to always stimulate him.
They only have a concentration span for around 10 minutes at a time anyway, and between feeds, naps, massage, play, tummy for them to keep themselves occupied for 30mins a time is not so bad.
You can try read to him, or get some barney dvd's / put on cbeebies then at least you know there's some good stimulation.
Mostly they just like mommies company so it doesnt really matter what you do, even if you paint your toenails or read a magazine - you wont get far though