Also the internal code name of a common fast Ethernet chipset produced by Sun Microsystems and used extensively in their Ultra series of workstations and Enterprise series of servers. It comes in on-motherboard, SBus and PCI variants, with the on-motherboard versions being either PCI or SBus internally depending on the system. Under Solaris and BSD, Happy Meal interfaces get the designation hme. (Happy Meal Ethernet)
These chips get their MAC address dynamically from the system when installed on Sun machines. It's possible to use the PCI versions in non-Sun machines, but if so the driver must provide a MAC address. This makes them slightly weird to use in PCs. Looking through the Linux driver source for this card, there are a number of comments that indicate it's rather buggy - but in practice they usually work fine.
A 4-port version, called the Sun Quad Fast Ethernet (qfe for short) is also produced, again in both SBus and PCI incarnations. The PCI versions use a 64-bit interface.