Here’s a quick spot-check on the memory usage on remote computer (or a few dozen computers). It uses WMI objects – Win32_ComputerSystem for the TotalPhysicalMemory and Win32_OperatingSystem for FreePhysicalMemory, TotalVirtualMemorySize (why did they add a 'size' here?), and FreeVirtualMemory.
Along the way, it does some formatting and conversions so everything uses the same units, and calculates the percentage of memory used. Very simple, but useful for things like when someone asks how many machines in the lab have less than 8GB of RAM