Like this:
// For "This text has some (text inside parenthesis)"
Regex RegexObj = new Regex(@"(([^)]*))");
// For "afasdfas (2009)"
Regex RegexObj = new Regex(@"((d+))");
Edit:
@SealedSun, CannibalSmith : Changed. I also use @"" but this was c/p from RegexBuddy :P
@Gregg : Yes, it is indeed faster, but I prefer to keep it simpler for answering such questions.
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…