You can block named executables through Software Monitoring or through security suite's application blocking. Therefore if you know the exe you want to block, this will do the job you want. However, if you want to block ANY games without first jknowing it exists, you need to look at Security Suite and the Host Intrusion Prevention component (HIPS), This allows you to do 'whitelisting' so that only your business apps can run and anything else is blocked. It is more complex to set up but more effective l;onger term. See this article for a little more info http://community.landesk.com/support/docs/DOC-3226.
Detecting if a device has dropped off the network:
Yes, can can set up Deviuce Monitoring where is will regularly ping a device to see if it is online. If it disconnects you can have it alert you.
Hope this helps.
Mark Star - MarXtar LANDesk Enhancements
Home of Power State Notifier & Wake-On-WAN for LANDesk