One of my favorite projects of the last several months was a Raspberry Pi cluster:

I’ve since set it up to run a local geth cluster, which makes running Mist or doing solidity development a little bit easier.

Here’s a build list:

• 4 x SanDisk Ultra 32GB microSDHC UHS-I Card with Adapter, Grey/Red, Standard Packaging (SDSQUNC-032G-GN6MA)
  
• 4 x Raspberry PI 3 Model B A1.2GHz 64-bit quad-core ARMv8 CPU, 1GB RAM
• 1 x Raspberry Pi 3 – Four (4) Layer Complete Stackable Dog Bone Case – Clear Stack Enclosure – Fits Pi 3 2 3B 2B B+ A+ B A – by Raspberry Vine
• 2 x Cat6 Ethernet Cable 2 Pack-5 Feet Black,RJ45,Snagless RJ45 Flat CAT6 Patch Cable
• 1 x Mini USB Power Strip, 4 Port USB charger station 5V 2.1A-1A 21W Travel Charging Strip Outlets 5ft Extension Power Supply Cord With Universal Flat Wall Plug 100V-240V Input USB Power Sockets (Blue)
• 1 x Zeal Tech 4-Pack 6 foot High Speed USB to Micro USB Charging Cables Android Charger Cord for Samsung Galaxy S7 Edge/S6/S5/S4,Note 5/4/3,HTC,LG,Nexus