I am guessing you need a way to stop the fussing, right? I had a very active one too (she's three now, and still active!) and I know how challenging it can be. One of the best toys we had is this Baby Counting Pal by LeapFrog: http://www.toysrus.com/product/index.jsp?productId=2649282. My daughter LOVED the classical music, and if you do the "Classical music medley" it will play for a couple of minutes. It will take quite a while for your baby to learn how to push the buttons himself (I think my daughter was close to two), but this is the one thing that calmed her consistently and kept her entertained for many, many months. Just don't try to use it in the car because you won't be able to push the buttons for him. I used to attach it to my dd's stroller when we were out walking, and use it like a boombox! She loved it!
Anyway, if your son is anything like my daughter, he'll be easier entertained as he gets more mobile (especially when he can finally walk). The active ones usually do all the physical things sooner, so hopefully that is something you can look forward to soon (at least crawling). In the meantime, just be creative and know that sometimes he'll be fussy. Try to just let him have some time on the floor when he can explore all on his own, especially once he can crawl. That always seemed to make my daughter the happiest.
Oh, and don't forget good old fashioned face time with mom! Singing, playing little piggies with his toes, peek-a-boo, talking to him and pointing out everything in his world, etc. are all ways to engage him that don't require a trip to the toy store. And sometimes this is really what babies crave most. Hang in there, the day when he can entertain himself for a bit WILL come!