This is a great opener that gets people moving to 4 corners of the room and allows the presenter to assess the skill levels of the participants.
Explain the levels of proficiency that go along with the roads. Start with a fun idea like skiing, BBQing, Knitting. Have participants move to the corner that represents their level of expertise. Introduce themselves to someone new and explain why they put themselves in this group. Then move on to your PD related skills - Web 2.0, Digital Storytelling, Photography, etc.