The adjective "boring" is ennuyeux. So "you are boring" is Tu est ennuyeux (informal) or vous êtes ennuyeux(formal).
Because of the spelling, this would be the same for speaking to a man, woman, or multiple people.
aburrido
Facebook es aburrido
Los libros son aburridos
gente viejos aburridos
Translation: Este cuento es aburrido.
Translation: Es aburrido aquí.
Translation: Estoy aburrido.Note that if you use "ser" and say "soy aburrido" it means "I am a boring person."
Translation: Hoy fue un día aburrido.
boring = aburrido/a(s) (male/female(plural))
Era aburrido/a (masculine/feminine 'it') Pronounced 'AIRah ahbooRREEthaw/ah' ('th' as in 'the')
Translation: Hoy era aburrido.However, it is much more idiomatic to say, "Hoy me aburró." meaning "Today bored me."
Aburrido is boring. One thing to watch is the use of ser and estar with this. Estoy aburrido means "I am bored". Soy aburrido means "I am boring".