Mac Mini Servers
I had an 'other duties as assigned' side gig about a decade back, helping the company events staff put on tech trade shows. We used to ship around a big rack with Dell servers, lots of money. I acquired 4x Mac Mini servers with maxed out CPU, RAM, and added Thunderbolt external disks. Virtualized all the physical servers and loaded them up on Fusion. Our 6 foot tall hard side shippable equipment rack transformed in to a luggable suitcase and a hand truck.
One of the classroom labs demonstrated a web gateway product, which meant I needed extra NICs. The Thunderbolt drives had a daisy-chain port, so I added an ethernet adapter. Ended up with all the event traffic running through that external hard drive & Thunderbolt cable (we hosted our own WiFi, cheaper than using the convention center's system). The Mac Mini never missed a beat and no one realized the diminutive nature of the infrastructure we were using. Worked great!
Cheers to Apple's little power-house PC!