Sending .exe or other unacceptable extension through msn or email

Trick: You can send the file by changing the file extension. Of course, another way is to rar or zip it.

Method:
1) My Computer > Tools > Folder Options... > View > uncheck "Hide extension with known file types"
2) I would suggest changing to extension .txt as almost all systems will accept that
3) Rename it. Eg. Someprogram.exe to Someprogram.txt
4) An message appears stating that "If you change a file name extension, the file may become unusable. Are you sure you want to change it?" Ignore it and just click "Yes"
5) The file name is changed and you can send it to your friend. His firewall will not block the file anymore. However, your friend would need to know how to do the reverse so that the file is still usable.