Sending an exe file with Gmail : zip the .exe, rar the resulting .zip, now zip the .rar and rename it to .doc … Sometimes things are so simple with GMail …
Update: ok, this was more a joke when I was upset than a real tip. Since this page gets some referral from search engines with people really looking for Gmail tips, here is a much more simple way to send your .exe files :
Rename to yourfile.-exe (or yourfile.-zip)