I have guests.
'Ospiti' — OS-pi-ti. Three syllables, stress on the first. It's a proparoxytone.
Use when out-of-town relatives or friends are staying with you. In Italian culture, being a host is a primary duty that overrides all other social commitments.
'Ho gli ospiti' is one of the most powerful cancellation phrases in Italian because hospitality is sacred. Once you declare you have guests, everyone understands you are fully committed to them.
Sono arrivati i parenti da fuori.
Relatives have arrived from out of town.
'Da fuori' (from outside/out of town) — implies a long journey and serious visit
Ho mia sorella a casa per il weekend.
My sister is at my place for the weekend.
Specific — family visits are unquestionable obligations in Italy
Ho degli amici che dormono da me.
I have friends sleeping over at mine.
Less formal — friends as guests also creates a full social obligation
When Italians have guests, they dedicate themselves entirely to them — cooking elaborate meals, accompanying them everywhere. It's considered disrespectful to leave guests unattended to attend other social events.