unexpected
extraordinary
improbable
more than expected
out-of-the-way
past expectation
sudden
surprise
unannounced
unanticipated
undivined
unforeseeable
unforeseen
unguessed
unhoped for
unpredictable
unpredicted
unprepared for
without warning
unacknowledged
unappreciated
unasked
undesired
undreamed-of
unescorted
unhonored
uninvited
unlamented
unlooked-for
unnoted
unreckoned
unrecognized
unrecorded
unscheduled
unsought
untapped
unwelcomed
unwept
heralded