Ouch! I was much luckier. The impact and circumstances sound about identical. Hitting on the side with Elbow/arm extended at time of impact allowing the ribs to take a direct hit. Glad to hear you're healing up!
Like you said, the ribs clunking around doesn't really hurt, just feels odd. I think mending has started already. They have been itching like crazy the last couple of days and hadn't clunked once yesterday until after a bad sneeze which I think knocked them loose again (Man sneezing sucks...Ow).
I was eyeing the dirt bike a bit today and thinking about trying some slow speed balance loops around the yard.... decided descretion is the better part of valor. Think I'll wait a bit longer.