think of a fun online learning application that can run unsupervised on my consolidated server

 - cheap to run
 - fun to interact with
 - online learning
 - understandable
 - minimal cpu and ram requirements (2 VPU, 2GB mem, 60GB sdd)
 - no GPU

allowed tech:
 - rust w/candle
 - c++
 - java
 - Go

no pytorch. no python.

problems areas:
 - general online learning for neural networks
 - interesting memory experiments with llms (microgpt adjacent)
 - graph rag something?