([A-Z][a-z0-9]+)+
Assuming English. Use appropriate character classes if you want it internationalizable. This will match words such as "This". If you want to only match words with at least two capitals, just use
([A-Z][a-z0-9]+){2,}
UPDATE:
As I mentioned in a comment, a better version is:
[A-Z]([A-Z0-9]*[a-z][a-z0-9]*[A-Z]|[a-z0-9]*[A-Z][A-Z0-9]*[a-z])[A-Za-z0-9]*
It matches strings that start with an uppercase letter, contain only letters and numbers, and contain at least one lowercase letter and at least one other uppercase letter.
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…