To put your Mac to sleep, while controlling any Apple application press and hold the play button for 3 seconds. (Please note that Plex will intercept this functionality and perform its own behavior if Apple remote functionality is ‘always running’).
To wake your Mac, just open Rowmote and let it connect.
Waking your Mac requires:
• The "Wake for network administrator access" option must be enabled in System Preferences -> Energy Saver. It may be called “Wake for network access” or “Wake for Ethernet network access.” If it says “Ethernet” your computer supports waking only over a wired Ethernet connection and not over wireless. Apple details these settings, with screenshots, in Mac OS X v10.6: About Wake on Demand.
• The Mac must be connected to a power source. It must have been connected at the time it went to sleep.
• Mac OS X 10.6 for wireless waking. All versions of Mac OS X support Ethernet (network cable) based waking.
• Wireless waking on Airport Extreme and Airport Express based networks works best if the wireless network is listed first in the Preferred Networks list via the Network pane of the System Preferences. As Apple explains in About Wake on Demand, the wireless network priority can be set within the Network pane of System Preferences using the following steps:
1. From the Apple menu, choose System Preferences.
2. From the View menu choose Network.
4. Select AirPort from the list of network interfaces.
3. Click the Advanced button.
5. In the Preferred Networks list, click and drag the name of your network that uses Wake on Demand to the top of this list.
6. Click OK to save the settings.