Recent　experimental　developments　have　brought　into　focus　optomechanical　systems　containing　multiple　optical　and　mechanical　modes　interacting　with　each　other.　Examples　include　a　setup　with　a　movable　membrane　between　two　end-mirrors　and　＂optomechanical　crystal＂　devices　that　support　localized　optical　and　mechanical　modes　in　a　photonic　crystal　type　structure.　We　discuss　how　mechanical　driving　of　such　structures　results　in　coherent　photon　transfer　between　optical　modes,　and　how　the　physics　of　Landau-Zener-Stueckelberg　oscillations　arises　in　this　context.　Another　area　where　multiple　modes　are　involved　are　hybrid　systems.　There,　we　review　the　recent　proposal　of　a　single　atom　whose　mechanical　motion　is　coupled　to　a　membrane　via　the　light　field.　This　is　a　special　case　of　the　general　principle　of　cavity-mediated　mechanical　coupling.　Such　a　setup　would　allow　the　well-developed　tools　of　atomic　physics　to　be　employed　to　access　the　quantum　state　of　the　＇macroscopic＇　mechanical　mode　of　the　membrane.　©　2011　Académie　des　sciences.