когда-нибудь

Adverb

 * 1) (indefinite adverb) sometime (or other), one day
 * 2)  ever (in the past)

Usage notes

 * The particle imparts a sense of indefiniteness similar to English any or ever. The form когда-нибудь is usually associated with questions and negatives (like anytime), while  is associated with affirmatives (like sometime).