I put together a web application to help with maintenance mode. This was my first attempt at building a web application so I'm sure there are inefficiencies and better ways to do it - so be kind with the comments!
I wrote this tool because I haven't seen anything that allows you to setup maintenance mode for remote systems without either having to logon to the RMS, use the operator console or install software/powershell on the remote systems. This utility does a few things
-Operates on both individual agents and groups
-Allows 'right now' configuration of maintenance mode
-Allows future scheduling of maintenance mode
-Displays systems currently in maintenance mode
-Seems to work for both OpsMgr administrators and standard, non-OpsMgr, users by making use of the account configured in the web page application pool. I say seems because I've only done limited testing!
I don't know if I will update the tool further and it is provided AS IS without warranty or support. Feel free to update it yourself if needed. I started a logging section but ran out of time so just commented out what I had.