Sawblade Software announced the $44 USD Power Game Factory today. This program is geared to designing side scrolling action games for the Mac, and "is capable of producing games similar to many of the most highly regarded 8-bit and 16-bit console video games, but with far superior graphics and sounds. Best of all, no programming is required."
I especially like the last question in the mini FAQ in the sidebar: "Can I make games for Windows? Never." Check it out.