String[] projection = new String[] { BaseColumns._ID};
    String selection = CalendarContract.Events.DTSTART + " <= ? AND "
            + CalendarContract.Events.DTEND + ">= ? AND "
            + CalendarContract.Events.AVAILABILITY + "=="
            + CalendarContract.Events.AVAILABILITY_BUSY;

    Cursor cur = ctx.getContentResolver().query(CalendarContract.Events.CONTENT_URI, projection,
            selection,
            new String[] {String.valueOf(System.currentTimeMillis()), String.valueOf(System.currentTimeMillis())},
            null);