According to Official Guinness Records,
The longest magic show performed at the same venue by an individual before a paying audience was achieved by Richard Smith (UK) whose show ran for 30 hr 45 min on 7–8 August 2004 at the Liverpool Moat House, Merseyside, UK.The event was organized to raise funds for 15 year old Chris Hardman's (UK) cancer treatment. Richard went for 11 hr 20 min without repeating a trick and in all performed 331 tricks.
For a complete list of 2004 records, please visit 2004 Guinness Records in United Kingdom.