Heads are bowed, hearts racing, the music cued and . the projector screen fails to light up behind us. Luckily, our audience, still basking in the warm glow from our first act (a song and dance number from the musical Hairspray), does not seem to mind the trillionth technical failure of the day.
We decide to plough ahead and the whole form launches into a rousing rendition of "They're trying to make us go to Year 8, but we won't go, go, go" to the tune of Amy Winehouse's "Rehab". Suddenly, their faces are illuminated and the sing-a-long sheet appears above them so the rest of the year joins in. I start to breathe again.
Five years ago, following a flash of ingenuity from a couple of creative heads of year, our school introduced a celebration assembly for each year group. Since then, every year in the last week of the summer term we set aside a morning or afternoon to give each form a chance to celebrate its successes. Form tutors get to present their forms with awards - not all of them serious - and the forms perform for the rest of their year group.
This annual event builds momentum as pupils progress through the school, culminating in their leavers' assembly in Year 11. On that day, staff and students jostle for places, with tissues at the ready. The head boy and girl spend weeks preparing their speeches. After all, they are summing up their five years at the school and addressing their peers directly, giving voice to their feelings.
The headteacher, who for four years has held back, now has a chance to impart his final words of wisdom as the Year 11s fly the nest. The anticipation is palpable as he climbs on to the stage and what has previously only been hearsay begins to become true.
To make this annual event a success, form tutors need to show a degree of commitment. There are rehearsals during lunchtime or after school, perhaps even auditions and Simon Cowell-style cutting of acts that are too long. Some tutors even take a turn themselves.
Rampant advances in technology help. Music can now be bought and burnt easily from iTunes, Windows Movie Maker can turn still images into films with soundtracks charting the growth of the pupils, PowerPoint images can be shown on a loop, and the website www.sheetmusicdirect.com is great for budding musicians.
There is also a wealth of resources to be plundered in your school. This is a good time to call in favours from colleagues (especially in dance, drama or music) - for example, readings from the English department or digital camera loans from media studies.
But if it's not possible to put on a major production, and your group is moving on to pastures new, simply ask pupils who is leaving at the end of term and where they are going. Point out that it is normal to feel sad, happy, excited and nervous at times of transition.
After all, the biggest resource is the enthusiasm from pupils. These celebration assemblies turn even the most disparate form into a supportive and happy bunch.
Katy Poole is a drama teacher at Dorothy Stringer School in Brighton. For more leavers' assemblies, visit the resources section on www.tes.co.uk.