April is National Autism Awareness Month. Take a few minutes to learn on www.autismspeaks.org. You'll most likely understand at least one adult or child you know a lot better.
Taken from the Autism Speaks website:
The following behaviors are often associated with Asperger syndrome. However, they are seldom all present in any one individual and vary widely in degree:

• limited or inappropriate social interactions
• "robotic" or repetitive speech
• challenges with nonverbal communication (gestures, facial expression, etc.) coupled with average to above average verbal skills
• tendency to discuss self rather than others
• inability to understand social/emotional issues or nonliteral phrases
• lack of eye contact or reciprocal conversation
• obsession with specific, often unusual, topics
• one-sided conversations
• awkward movements and/or mannerisms
• "robotic" or repetitive speech
• challenges with nonverbal communication (gestures, facial expression, etc.) coupled with average to above average verbal skills
• tendency to discuss self rather than others
• inability to understand social/emotional issues or nonliteral phrases
• lack of eye contact or reciprocal conversation
• obsession with specific, often unusual, topics
• one-sided conversations
• awkward movements and/or mannerisms