dsmith@ip-xx-xxx-xxx-xx:~$ groups dsmith
dsmith sudo py
dsmith@ip-xx-xxx-xxx-xx:~$ sudo chmod -R g+rwxt /usr/local/virtualenvs
dsmith@ip-xx-xxx-xxx-xx:~$ ls -al /usr/local
...
drwxrwxr-x 2 root py 4096 2010-02-17 19:36 virtualenvs
dsmith@ip-xx-xxx-xxx-xx:~$ echo "Hello World" > /usr/local/virtualenvs/test.txt
bash: /usr/local/virtualenvs/test.txt: Permission denied