。
She almost never goes to bed before eleven.
Literal
She [topic-は] practically rarely 11 o'clock before [at-に] sleep [thing-こと] [contrast-は] not-exist.
This stacks a remarkable amount of negation hedging: まず ('on the whole, practically'), めったに ('rarely'), and the ことはない frame ('there is no occurrence of'). The combination produces an almost categorical 'practically never' — Japanese has a rich grammar of incremental negation, and chaining these adverbs and patterns lets the speaker dial in exactly how strong the denial is. ことはない here means 'there is no instance of [her sleeping before 11],' built from the nominalizer こと plus negative ある.