News outlets such as the Toronto Star are reporting on the publication by The Smoking Gun of Mariah Carey’s 2010 concert rider:
No more Cristal Champagne and bendy straws for singer Mariah Carey. She’s all grown up now.
The concert rider for the just-turned-40 superstar excises a lot of the wretched excess and control freak details of past year
Performers’ contract riders (really just an attachment to the main contract which sets out certain items in a level of technical detail which is unsuitable for the "contractese" which permeates the main contract) can address matters ranging from stage construction to the brand of bottled water to be provided backstage. The rider on one of Carey’s previous tours included some amazingly detailed instructions regarding catering (a box of bendy straws, a director’s chair and spinach with hot bacon dressing are just some of the highlights). The rider for the current tour, while being touted as less frivolous, is, if anything even more detailed than the previous rider, and includes its own interesting elements (such as the need for "8 tall, leafy plants").
Helpfully, The Smoking Gun has compiled an astounding collection of dozens of contract riders for acts ranging from Guns N’ Roses (1 box of assorted candy bars; 1 assortment of adult magazines) to Lil Wayne (2 bottles of Grey Goose vodka; police escort) to Kenny Rogers (4 wedged lemons; 2 pounds of M&Ms).
Snopes.com offers some thoughts on the motivations for complicated riders, using the legendary (but true) Van Halen requirement of "no brown M&Ms" as an example:
The M&Ms provision was included in Van Halen’s contracts not as an act of caprice, but because it served a practical purpose: to provide an easy way of determining whether the technical specifications of the contract had been thoroughly read (and complied with).