The Prop. 8 ban on same-sex marriage is certainly not the first California initiative to garner huge national attention. Historically many of our ballot measures -- like the 1978 Prop. 13 cap on property taxes and the 1996 Prop. 209 curb on affirmative action in public institutions -- have made a big impact on politics and policy beyond the state.
The California initiative process was born in 1911 as the result of a special election called by Gov. Hiram Johnson. Citizens approved the enabling constitutional amendment by a margin of 168,744 to 52,093 votes. "A History of California Initiatives" is a good study that includes a complete list of ballot measures, plus interesting statistics on their subject matter and success/failure. Did you know, for example, that voters approved only 99 of the 1,187 initiatives titled and circulated between 1912 and 2002?
The Hastings College of Law at UC Berkeley provides comprehensive, searchable databases of information on California initiatives and propositions from 1911 to 2000. These include full-text of ballot measures and accompanying material such as legislative histories and scans of voter pamphlets. You can search by keyword, year, number and pass/fail status. For the full text of newer initiatives (2004-current) see this Attorney General web page. For the full text of newer propositions (1996-current) see this Secretary of State web page.