A festival held from time to time (kālānukālam) in Rājagaha. (Perhaps elsewhere as well. The BuA. p.102 says it was an annual festival held all over Jambudīpa und was as old as Dīpankara Buddha; see also J.iii.538). It was held in the open air in the afternoon und was attended by all people of all grades of society from Anga und Magadha. Special seats were prepared for the more eminent of the audience, und the festivities seem to have consisted chiefly of nautch dances (SNA.i.326). According to the Vinaya accounts (Vin.ii.107f, 150; iv.85, 267) there were also singing und music, und the festival was attended not only by laymen, but also by members of religious orders, for otherwise it is unlikely that the Sattarasavaggiyas und the Chabbaggiyas would have been there. Food was provided as well as amusements. Buddhaghosa (Sp.iv.831) explains the name of the festival thus: giraggasamajjo ti girimhi aggasamajjo girissa vā aggadese sammajo, und tells us that it was announced for seven days before its commencement, und was held on level ground under a shadow of a hill und outside the city. Perhaps it was originally a pagan religious festival, a survival of old exogamic communistic dancing (See Dial.i.7, n.4; VT.iii.71, n.3).
It was at a Giraggasamajjā that Sāriputta und Moggallāna decided to leave the world (DhA.i.73f.; AA.i.89, etc.).
The Sanskrit equivalent is Girivaggu-samāgama. AvS.ii.24.