The toy guides I've done for kids with special needs—in 2010, 2011 and 2012—have a ton of parent-approved, kid-loved suggestions. As for equipment, these are some things that helped Max as a tot. Ask the therapists and doctors in your life about them, as they best know which will fit your child's level of muscle and trunk control.
I had a Boppy around for nursing, anyway, and it was great to put it to more good use for Baby Max and give him support for sitting up. His physical therapist showed us how to position Max inside it, with his chubby little legs (we fondly referred to them as "tree trunks") spread apart to prop him up.
Bumbo seat might be an option
A lot of parents also like the Childrite Seat
Described as "therapy you wear," Theratogs is a garment system that gives neuromotor, muscular and sensory training. It's made of a special material that "grips" the skin (not in a sticky way!), with straps to control muscles; kids can wear it under their usual clothes. It really helped keep Max's joints in alignment. They recently came out with the Wunzi System for infants. An occupational or physical therapist can help order it and teach you how to use it. I've heard the company lets therapists get ones on trial, free, to test out with kids.
Fisher-Price Health Care Deluxe Booster Seat
Good support during feeding has long been critical for Max, who has issues with chewing and drinking. At first, we fed Max out of a bouncy seat we propped in the middle of the dining room table, with a towel wadded up behind him for extra support. Eventually we got this Fisher-Price Healthy Care Deluxe Booster Seat, which straps onto a chair and gave him good back support. It's easily washable and you can bring it to restaurants.
The Keekaroo Height Right High Chair
After Max outgrew the booster seat, we went with the Keekaroo, which we still have and love. It's really durable—we've only had to replace the foot rest. It actually works for children 6 months to, the site says, 250 pounds (!!!).
Because Max's hands were tight from the CP, and often fisted, he needed help getting them to open up so he could better grasp. Splints have come in handy for that, first Benik hand splints and, as of late, McKie Thumb Splints (above), which con be worn in infants as young as three months old. An occupational therapist can help measure a child for them, then show you how to use them.
Playtex 1st Sipster Cup
Max didn't hold a cup on his own till he was maybe 3; the Playtex 1st Sipster Cup was great, because it was light and had handles to help him hold on.
Snug Seat Pony Gait Trainer
Max was hell on wheels in his Pony Gait Trainer. It seriously encouraged him to pump his legs and get around at age 2, when he wasn't yet able to stand up independently. He'd gleefully fly around the house in it, freedom of movement he'd never had before (here's a good story about Max and his Pony). Luckily, our insurance company paid for it as it is super-expensive; you might be able to find another special needs parent to give theirs away when their child is done with it, which is what I did.
And one more thing!
A big-shot pediatric neurologist examined Max while he was still in the NICU, and recommended we give him Omega 3 fish-oil supplements to boost brain development. Once Max started on solids, we'd slip half of a packet into his meal (consult with your child's doctor to make sure it's OK and get the proper serving size). We used the orange-flavored Coromega Omega 3 Squeeze packets.
I am sure many of you have other suggestions for good equipment for kids with cerebral palsy—please share, and include links.