Hella can mean a few things, as a popular and very regional Northern California term for "very" or "lots of".
Hella the Band
Hella is a popular math rock band from Sacramento that played their first show ever at the Dam Haus in Davis in support of Lightning Bolt, Pink & Brown, and Total Shutdown.
See their write up at Allmusic.com
Hella the SI Prefix
UCD physics student Austin Sendek is pushing for Hella to be adopted in the same way kilo or mega are standardized prefixes. He's seeing an ISO standard of 1027, which would follow zetta (1021) and yotta (1024).
Written out, it would be 1,000,000,000,000,000,000,000,000,000, which is a hella zeros.
- SacBee article, 2010-03-02
