I just sold a PR 6 domain to someone for $10 because the earlier today, the Google PR was acting up on me and displaying PR 3. i thought my domain had lost its PR and I decided to sell it. Shizt.
Got a $1k offer for a blog domain and while considering it I noticed it's PR had gone up to 6 (got some unexpected links) so decided to keep it - next day the pr dropped to 4