Upgrade your office chair with the Memory Foam Seat/Chair Cushion by Royi ($35) — it's designed to restore your spine's natural lumbar curve and correct posture, relieving lower-back pain, numbness, discomfort from sciatica, herniated discs, tailbone injuries, pregnancy-related aches, and hip tension. The pillow's design features a rubber bottom to keep you from slipping off your seat and foam cushioning that's guaranteed not to flatten.