Wonderful guy, wonderful cause, wondering when I'll see his smile next…

There's an important lesson here:

Bullington, an early executive at search engine Excite and a prolific angel investor in high-profile startups like Flickr, Gowalla, and Digg, was riding his bike across the US to raise money for a nonprofit, Carolina For Kibera. While on Highway 10 in Bartlesville, Okla., Bullington seems to have lost control of his bike going about 27 miles per hour.

1. Be careful when biking. It's very easy to lose control.

2. Be particularly careful when going downhill.

3. Always wear a helmet.