It’s not often that a performance of Purcell’s King Arthur requires its entire cast of singers to strip down to very tight Union Jack boxer shorts. It’s not often either that the audience find themselves actively encouraged to talk over the music, yet both were unexpectedly and riotously true last night at the Spitalfields Festival. Pairing Baroque big-hitters The English Concert and I Fagiolini, there was nothing half-hearted about this semi-staging of Purcell’s semi-opera. It promised much and delivered more, and while those listening live on Radio 3 might have enjoyed better textural balance, they can’t have had nearly as much fun as the sell-out crowd sweltering away in Shoreditch Church.

Travelling by Eurostar, or plane, to the continent and buying a ticket, all for less than the cost of a Covent Garden stalls seat, might entice if you wanted to see a certain opera, singer or conductor. But to go so far for the look of a staging? Well, the Catalan company La Fura dels Baus’s phantasmagorical ENO production of Ligeti's Le grand macabre has left some of us hungry for more, which so far means going abroad to find it. Ultimately their latest Wagner doesn't always rise to the expected visionary heights, but it does boast world-class music-making and, wonder of wonders, real interaction between the singers on a human scale.

Mozart's Idomeneo is subjected to a famous bit of abuse in Milos Forman's Amadeus. "A most tiresome piece," a courtier critic sniffs. "Too much spice. Too many notes." As it happens, not a wholly inaccurate statement. The work is quite an exotic curry of an early Classical opera.

Donizetti's L'elisir d'amore must be the only opera from whose central lesson one can actually learn something. Its message - drink, chill out, back off and the girl will be yours - is as good a moral guide to life as any. But it was still surprising to leave Glyndebourne last night satisfied.

Public feuding, private sorrows: the elemental passions of Verdi's Ligurian power struggle haven't had a vivid London staging since the Alden-Fielding ENO classic gave it a guiding (or, according to taste, hindering) giant hand in the late 1980s. Dmitri Tcherniakov, the most disciplined opera director to have come out of Russia, was a clever choice for the company to invite to the Coliseum.

Nothing says summer opera quite like the skittish melodies and Neapolitan oom-pah-pah of a Donizetti overture. It doesn’t get much cheekier or more playful than this, the kind of music that makes you long for a pea shooter to pelt opera-goers with a stealthy fire of peanuts, or daub the bald head of the concert-goer in front of you during his Act II siesta. When set against the greenery and obbligato peacocks of Holland Park, a work like Don Pasquale makes sense in a way it scarcely can in the corseted confines of a traditional opera house. Add a witty staging by Stephen Barlow, and Richard Bonynge – the godfather of bel canto – in the pit, and summer sunshine is guaranteed, whatever the weather.

Tosca-at-Covent-Garden is a commodity, like bacon-for-breakfast - a pricier commodity, to be true, at officially up to £229.50 a seat, but in both cases people want to get what they expect. For the final performances next month in this summer revival, with the megastars Angela Gheorghiu, Jonas Kaufmann and Bryn Terfel, all seats are sold, with touts on eBay offering a pair of amphitheatre seats at bids over £300.

They say that old sins cast long shadows, but these are nothing compared to the shadows cast by old productions. To set Verdi’s Rigoletto in 1950s America inevitably courts comparison with that operatic patriarch, Jonathan Miller’s New York Mafia reworking.

Tamino and Pamina, in Mozart’s great masonic opera, go through fire and water, as well as trials spiritual and emotional, before achieving their sunlit triumph at the end of it all. They would have sympathy with Anthony Whitworth-Jones and his Garsington Opera team in what must have been quite as frightening a battle to locate, plan, design and build their new pavilion on the Getty estate at Wormsley, near Stokenchurch on the M40, within barely more than a year.