I recently used enamel paint to rehab the aggressively bright tiles in my kitchen backsplash. We couldn't afford a new backsplash, and I'd long resigned myself to hating our kitchen, but then it occurred to me to paint the offending tiles myself. Instead of a hundreds-of-dollars job, it cost about $40. Although a bit tedious, there's nothing complicated about the process. And the paint gives a really nice matte finish.
She also sent the link to her DIY instructions.