Problem: Windows instincts kick in and you want to Ctrl+Alt+Del your way out of a crashed program... or porn. or crashed porn.
Solution: Bring up the "Run Dialog"; with default shortcuts that's Alt+F2. Type in "xkill", then Enter. This will make your cursor an "X" or something - use it to click on the misbehaving window (you can Alt+Tab to get to the appropriate window).
Note: If you click on the taskbar icon, it will just shutdown tint2. Restore the taskbar by typing "tint2" in the Run Dialog (Alt+F2).
Shortcut: You can bind the xkill command to a handy shortcut. Edit your OpenBox:
Main Menu > Settings > Openbox > edit rc.xml
Scroll to <keyboard> - add your fancy new shortcut. This one will bring up the xkill with Ctrl+Alt+Q.
<!-- Keybindings by Emily --> <keybind key="A-C-q"> <action name="Execute"> <startupnotify> <enabled>true</enabled> <name>XKill</name> </startupnotify> <command>xkill</command> </action> </keybind>