There is a mode that MBP's can operate in with the lid closed, it's called "clamshell mode". To operate in clamshell mode the MBP needs to be connected to an external monitor and have either or both of an external keyboard or mouse connected. These can be USB devices but they can also be bluetooth devices so long as they're paired with the MBP in advance of it entering clamshell mode. Once the external monitor, keyboard and/or mouse are connected and working the lid can be shut which puts the MBP to sleep. It can then be woken up with a mouse click or keypress on one of the external devices and the display will appear on the external screen. To operate in clamshell mode your MBP must be connected to mains power, it does not work on battery power.
I want to be able to power up my mac pro with the lid closed. Is there a way to do this?
Thanks for your help.
Yes, several actually, if you have the Apple Remote that will start it up with the lid closed, plugging a monitor in will also start it, plugging a drive into one of the USB slots likewise. This is in addition to Zyriab's accurate information regarding the kbd/mouse methods.