Quick answer
A play is спекта́кль (masculine), a film showing is сеа́нс, and the interval is антра́кт.
The event
теа́трteátrtheatre
спекта́кльspektáklplay, performance (m.)
бале́тbalétballet
о́пераóperaopera
кино́kinócinema (indeclinable)
сеа́нсseánsfilm showing
антра́ктantráktinterval
The seats
парте́рpartérstalls
балко́нbalkónbalcony
рядryatrow
ме́стоméstoseat
ло́жаlózhabox
биле́тbilétticket
гардеро́бgarderóbcloakroom
The people
актёрaktyóractor
актри́саaktrísaactress
режиссёрrezhissyórdirector
зри́телиzríteliaudience
бра́во!brávobravo!
аплодисме́нтыaplodisméntyapplause
Buying and going
Два биле́та в парте́р, пожа́луйста.Two tickets in the stalls, please.
Во ско́лько нача́ло?What time does it start?
Ско́лько дли́тся спекта́кль?How long is the performance?
Где на́ши места́?Where are our seats?
Э́то мой ряд?Is this my row?
The coat, again
As in museums, the гардеро́б is obligatory in a theatre: coat and large bag go in before you reach the auditorium. People also dress up noticeably more than in most of Europe, and arriving after the start can mean waiting until the interval.
Russian films worth starting with
For learners: Ирония судьбы (a New Year fixture every Russian knows by heart), Москва́ слеза́м не ве́рит, and Soviet animation such as Ну, погоди́! — almost wordless and genuinely funny. Subtitled first, then without.
Typical mistakes
Я иду́ на кино́.
Я иду́ в кино́.
Cinema takes в; a specific showing takes на: на сеа́нс.
моя́ спекта́кль
мой спекта́кль
спекта́кль is masculine despite the -ь.
Check yourself
What is антра́кт?
The break in the middle.